other: Comparable to guideline study with acceptable restrictions (use of an irritating dose for challenge exposure; lack of data on test substance)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1 995

Report Date:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

(use of an irritating dose for challenge exposure; lack of data on test substance)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A non-LLNA test is available that was performed prior to the current data requirements, stipulated in Regulation (EC) No 1907/2006. In accordance with the same Regulation, the data were included to avoid unnecessary testing.

RANGE FINDING TESTS:A primary irritation test (PIT) was performed to determine suitable concentrations for intradermal and epicutaneous induction. Therefore, three concentrations of the test substance (0.1, 1.0 and 5.0% v/v in peanut oil) were administered intradermally to 2 animals per concentration. The injection sites were evaluated 24 and 48 h after injection. None of the injection sites for the 5.0% animals showed skin corrosion or irritation at either the 24 or 48 h observations. Therefore, 5% of the test substance was chosen for intradermal induction. The PIT also indicated that 100% of the test substance applied topically produced mild to moderate irritation whereas 50% of the test substance was non-irritating. Therefore, concentrations of 100% of the test substance were chosen for the topical induction dose and 50% for the challenge dose, respectively.

Due to the fact that the challenge dosing with 50% test substance was more irritating than is ideal for the challenge and rechallenge phases, the concentration for rechallenge dosing was lowered to 10% of the test substance.

Any other information on results incl. tables

In the test group and the irritation control animals, the 3 intradermal injections of the intradermal induction produced slight to moderate redness around the injection sites at either 1 and 24 h after injection. The topical application of 100% of the test substance for 24 h under occlusive conditions leads to very slight to well-defined erythema in 18/20 animals and severe erythema to slight eschar formation in one animal at the 1 and 24 h observations. Moderate to severe erythema formation was observed in one animal after 24 h. At the 1 h reading, very slight to slight edema were noted in 12/20 animals. At the 24 h reading, very slight to moderate edema were observed in 19/20 animals.

The topical application of peanut oil produced results similar to the treated animals. In all 10 irritation control animals, very slight to severe erythema and very slight to slight edema were noted at the 1 and 24 h observation time points.

The topical challenge dose of 50% test substance in peanut oil leads to very slight erythema in 11/20 animals and to well-defined erythema in 7/20 animals at the 24 h evaluations in test group animals. At the 48 h reading, 6/20 animals had very slight erythema, one animal had well-defined erythema and 13/20 animals were free of erythema. Very slight edema were observed in 4/20 treated animals at the 24 h observation and in one animal at the 48 h observation. In the irritation control group, the topical application of 50% test substance in peanut oil produced very slight erythema in 4/10 animals and well-defined erythema in 5/10 animals at the 24 h reading. At the 48 h observation, 6/10 animals had very slight erythema and one animal had well-defined erythema. Edema was not observed in any irritation control animal at the 24 or 48 h reading.

Since the severity of the erythema was similar between the treated group and the irritation control group and the incidence of erythema was higher in the irritation control group, the response was considered an irritation response and not a sensitization response. An examination of the individual animals' responses showed that the majority of the irritation scores decreased from the 24 h evaluation to the 48 h evaluation, which also is indicative of an irritation and not a sensitization response. However, since there was some irritation from the challenge application, it was decided to rechallenge at a lower concentration to confirm that the test material possessed no sensitization potential.

The rechallenge was performed with 10% test substance in peanut oil and produced very slight erythema in 4/20 animals at the 24 h observation. All animals were free of erythema at the 48 h evaluation. Edema was not observed in any treated animals at the 24 or 48 h observations.

In the irritation control group, topical application of 10% test substance in peanut oil leads to very slight erythema in 4/10 animals and well-defined erythema in one animal at the 24 h observation. All animals were free of erythema at the 48 h evaluation. Edema were not observed in any irritation

control animal at the 24 or 48 h observations.

Applicant's summary and conclusion

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

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